Add Policy-based Navigation (#5967)

* add permissions service

* start template helper

* match prefixed paths

* gate sidebar links

* land on first page user has access to

* show nav when user first logs in

* clear paths when user logs out

* add tests

* implement feedback

* show all nav items if no policy is found

* update onboarding wizard

* fix some unrelated tests

* add support for namespaces

* gate wizard

* unstage package and lockfile

ui/app/components/nav-header.js

@@ -1,5 +1,4 @@
 import Component from '@ember/component';
-
 export default Component.extend({
   'data-test-navheader': true,
   classNameBindings: 'consoleFullscreen:panel-fullscreen',